Using TLS-Measured Tree Attributes to Estimate Aboveground Biomass in Small Black Spruce Trees

Abstract

Research Highlights: This study advances the effort to accurately estimate the biomass of trees in peatlands, which cover 13% of Canada’s land surface. Background and Objectives: Trees remove carbon from the atmosphere and store it as biomass. Terrestrial laser scanning (TLS) has become a useful tool for modelling forest structure and estimating the above ground biomass (AGB) of trees. Allometric equations are often used to estimate individual tree AGB as a function of height and diameter at breast height (DBH), but these variables can often be laborious to measure using traditional methods. The main objective of this study was to develop allometric equations using TLS-measured variables and compare their accuracy with that of other widely used equations that rely on DBH. Materials and Methods: The study focusses on small black spruce trees (<5 m) located in peatland ecosystems of the Taiga Plains Ecozone in the Northwest Territories, Canada. Black spruce growing in peatlands are often stunted when compared to upland black spruce and having models specific to them would allow for more precise biomass estimates. One hundred small trees were destructively sampled from 10 plots and the dry weight of each tree was measured in the lab. With this reference data, we fitted biomass models specific to peatland black spruce using DBH, crown diameter, crown area, height, tree volume, and bounding box volume as predictors. Results: Our best models had crown size and height as predictors and outperformed established AGB equations that rely on DBH. Conclusions: Our equations are based on predictors that can be measured from above, and therefore they may enable the plotless creation of accurate biomass reference data for a prominent tree species in a common ecosystem (treed peatlands) in North America’s boreal.

Terrestrial Laser Scanning for Non-Destructive Estimation of Aboveground Biomass in Short-Rotation Poplar Coppices

“…This pattern is also observed when evaluating the correlation between the plot-level biomass and the TLS-derived metrics aggregated at the plot level. This result agrees with previous findings by [74] that compared the ability of Quantitative Structure Models (QSMs) and bounding boxing to estimate aboveground biomass in small Picea mariana (L.) trees, with a higher accuracy (R 2 adj = 0.89) for the bounding box in comparison to the QSM (R 2 adj = 0.82). In contrast, other studies such as [50,65] have demonstrated the superiority of slicing or voxelization over simpler methods in computing crown volume, crown structure, or aboveground biomass.…”

The Multisource Vegetation Inventory (MVI): A Satellite-Based Forest Inventory for the Northwest Territories Taiga Plains

“…This would be of particular value over areas where existing field data are extremely limited, and it provides opportunities to sample other vegetation types such as forested peatlands and wetlands and track recovery dynamics of burned areas. Combined with limited destructive sampling, this could enable the development of biomass models that rely on allometric predictors that can be measured from above, such as height and crown area [77]. One limitation mentioned in Section 5.4 was the estimation of AGB and age of small black spruce in peatlands.…”

Unmanned Aircraft System (UAS) Structure-From-Motion (SfM) for Monitoring the Changed Flow Paths and Wetness in Minerotrophic Peatland Restoration

“…Filter discussion; Section S5: Correlation between Topographic and Field Wetness; Figure S1: Gravimetric Soil Water Content (SWC) as a function of topography-based Saga Wetness Index (SWI) and the fitted regression lines. References [99][100][101][102][103][104][105][106][107][108][109][110][111] are cited in the Supplementary Materials. Institutional Review Board Statement: Not applicable.…”